The invention relates to the isomerization of diacyloxyolefins.
A very large variety of chemicals can be made from diolefins. One such group of chemicals is the diacyloxyolefins which are then easily converted to other various chemicals, such as the diols or glycols and the furans. As a specific illustration, 1,3-butadiene can be converted to 1,4-diacetoxy-2-butene and its isomer 1,2-diacetoxy-3-butene by various processes known in the art. The 1,4-isomer can be separated from the 1,2-isomer by fractional distillation as the 1,2-isomer is more volatile. The 1,4-isomer can then be hydrogenated to remove the double bond and to produce 1,4-diacetoxybutane which can then be converted to tetrahydrofuran by hydrolysis and cyclization. All of the above steps are well known in the art. It is readily apparent from the above illustration, however, that the overall process to produce tetrahydrofuran from 1,3-butadiene could be substantially improved by including an isomerization step to convert the 1,2-isomer to the 1,4-isomer. Although isomerization processes are known in the art that could be used to convert 1,2-diacetoxy-3-butene to 1,4-diacetoxy-2-butene, such processes generally require rather expensive catalysts that are useful for only a relatively short period of time. Besides producing tetrahydrofuran from 1,4-diacetoxy-2-butene, other chemicals such as diols or glycols also could be produced from various diacyloxyolefins and many such processes could likewise be improved by an effective or inexpensive diacyloxyolefin isomerization process.
Thus, an object of the invention is the isomerization of diacyloxyolefins.
Another object of the invention is an isomerization process that is both inexpensive and efficient in comparison to such processes known in the art.
These and other objects, aspects, and advantages of the present invention will be apparent to those skilled in the art from studying the specification and the appended claims.